Liquid storage

ABSTRACT

Apparatus for storing water, especially purified water, for use in a beverage dispenser is provided with a microbiological agent to kill or deter microbiological growth and maintain the quality of the water. The agent is provided in a physical form to promote contact with the water and may be renewable to maintain effectiveness of the agent over a period of time. In one arrangement, the agent is contained in a cartridge  92  arranged in a re-circulation loop  89  through which the water in a reservoir  80  is passed and returned to the reservoir  80.  The cartridge  92  and/or a carrier for the agent within the cartridge  92  may be replaceable to renew the agent. The agent may also be provided within the reservoir  80  and various arrangements for this are also disclosed.

[0001] This invention relates to the storage of liquids, particularlybut not exclusively water. For convenience it will be described belowwith specific reference to water.

[0002] There have been numerous proposals for the treatment of water topurify it and many of these proposals have been devised bearing in mindthat water quality and purity vary considerably from location tolocation and that a relatively simple treatment means is required thatcan be used in a wide variety of situations and that is, preferably,renewable.

[0003] Many of the known treatments involve filtration and heat stagesand are successful to greater and lesser degrees in providing aconvenient, economical means of providing water of acceptable purity inrespect not only of content of chlorine, heavy metals, organics,carbonates and the like but also in respect of microbiological quality.

[0004] Regardless of the actual treatment method used, many treatmentprocesses are devised to provide a reservoir of treated water which canbe drawn off for use as and when required, i.e. the treated water is notused immediately but must be stored for varying periods of time. Onespecific example is in the treatment of water for post-mix beveragedispensers in which a beverage is mixed from a concentrate and adiluent, usually water, at the point of sale. The water to be used mayhave been subjected to a purification treatment and it may then bestored in a suitable reservoir before being drawn off in a requiredamount for each beverage dispense.

[0005] Although such stored water may be of high purity and of highmicrobiological quality on entering the reservoir or other storagesystem, neither it nor the reservoir will normally be sterile. There is,therefore, always a risk that the microbiological state of the storedwater will deteriorate with time. Simple addition of microbiocidalmaterial to the reservoir has not proved to be a satisfactory solutionas adequate contact is difficult to achieve.

[0006] It is, therefore, an object of the present invention to provide aliquid storage apparatus in which this problem may be ameliorated oreliminated.

[0007] Accordingly the invention provides a liquid storage apparatus,the apparatus comprising a reservoir for the liquid, the reservoircontaining a microbiological agent to kill or deter microbiologicalgrowth, the microbiological agent being in a physical form to present asufficient contact area with the liquid to provide the required effect.

[0008] In a first general embodiment the wall of the reservoir may beformed of material, usually plastics material, in which themicrobiological agent is present or onto which it is coated. Thus theagent may conveniently have been compounded into the composition used toform the walls of the reservoir. The “walls” may, of course, include thefloor and roof and the agent may similarly be incorporated in conduitsand fittings of the reservoir. However, we have found that such anarrangement does not by itself provide the desired degree of contacttime and area to effectively treat all the water or other liquid thatmay be contained in the reservoir.

[0009] Thus in this embodiment of the invention, we have found that itis preferable to provide agitation means within the reservoir to promoteincreased water/wall contact or recirculation means to pass the waterout of and back into the reservoir. Both means may be used incombination. Where the water is recirculated, it may also be passedthrough, e.g. a cartridge, containing further microbiological agent, tofurther improve the treatment and contact time. The furthermicrobiological agent may be in any convenient form, e.g. granular or ina reticulated foam. A labyrinth may be provided in the cartridge in therecirculation line to further improve flow path contact time with theagent.

[0010] In a second general embodiment, the microbiological agent ispresent in the tank in an open cell, e.g. reticulated, foam, in fibre,or in granular form to provide the required surface area to allowadequate contact. It may be coated onto the foam, fibres or granules butit may be found more convenient for it to be compounded into thecompositions from which these bodies are formed.

[0011] The microbiological agent may be any suitable biocide orbiostatic agent and examples include triclosan, zinc pyrithione, silvercompounds and KDF. The latter is a metallic combination of copper andzinc, which is available in a variety of forms including granules, wooland reticulated foam.

[0012] The agent may be incorporated in a variety of readily availableplastics materials which can be processed by conventional meansincluding injection moulding, blow moulding, rotational moulding andextrusion for use in the first embodiment of the invention.Alternatively it may be incorporated in plastics compositions which areprocessed to a carrier form, e.g. reticulated foam, granule or fibrousform for insertion into the reservoir in the second embodiment.

[0013] In the second embodiment of the invention, the carrier form ofthe agent may be of volume to completely fill the reservoir, in whichcase a vent will be needed to allow filling of and drawing from thereservoir. For example, the reservoir may be completely filled withreticulated foam containing the agent and the water enters to fill thevoids in the foam and thereby ensures a good and sufficient contact areafor the agent to work. An air filter may be fitted into the vent.

[0014] Alternatively the reservoir may be a sealed tank, i.e. unvented,with sufficient headspace left during use to allow filling and emptyingto take place or it may contain a collapsible membrane as a barrier toatmosphere.

[0015] Alternatively the carrier may form a layer in the reservoirthrough which the water must pass on its travel from the reservoir inletto the outlet. The layer may be attached to the reservoir walls or takethe form of a floating layer of, e.g., foam or granules. Again thereservoir may be vented, with a filter, if desired.

[0016] In another arrangement the carrier may form a layer on the floorof the reservoir or be in a “sump” in the base of the reservoir.

[0017] Where a foam is used as the carrier for the agent, it may be usedin compressed or uncompressed state whereby the volume to surface arearatio may be enhanced by changing the cell size.

[0018] It will be appreciated that the carrier, e.g. the foam, canpresent an extremely large surface area to contact the water.Reticulated foam, for example, can absorb almost up to its own volume ofliquid thereby ensuing maximum effective use of the microbiologicalagent.

[0019] Embodiments of the invention will now be described by way ofexample only with reference to the accompanying drawings in which:

[0020]FIG. 1 is a diagrammatic representation of a reservoir tankaccording to the invention;

[0021]FIG. 1A is an enlarged view of an alternative form of a portion ofthe apparatus of FIG. 1;

[0022]FIG. 2 is a similar view to FIG. 1 of a second reservoir tank ofthe invention;

[0023]FIG. 3 is a similar view of a third reservoir tank of theinvention;

[0024]FIG. 4 is a similar view of a fourth reservoir tank of theinvention;

[0025]FIG. 5 is a similar view of a fifth reservoir tank of theinvention;

[0026]FIG. 6 is a similar view of a sixth reservoir tank of theinvention; and

[0027]FIG. 7 is a similar view of a seventh reservoir tank of theinvention.

[0028] In FIG. 1 a reservoir for water is a tank 10 having an inlet 11in its roof 12 and an outlet 13 in its floor 14. The tank is filled withreticulated foam 15 which has been impregnated with a biocide and/or abiostatic agent. A vent 16 in roof 12 of the tank allows water to befilled into and drawn out of the tank. The reticulated foam, which maybe polyurethane foam, may be replaced by granules which have been pouredin to fill the tank.

[0029] As shown in FIG. 1A, vent 16 may contain an air filter 17 of, forexample, 0.2 micron pore size.

[0030] In FIG. 2 a tank 20 has an upper housing 28 which leads into asmaller “sump” housing 29 extending below the floor 24 of housing 28. Asabove, the tank has an inlet 21 in its roof 22 and in this instance hasan outlet 23 from the base of sump 29. The sump 29 is filled withreticulated foam or granules containing the microbiological agent.

[0031] A vent 26 is provided in roof 22. This may again contain afilter, if desired.

[0032] In FIG. 3 a tank 30 has an inlet 31 in its roof 32 and an outlet33 in its floor 34. A vent 36, with or without a filter, is againprovided in roof 32. A blanket 35 of foam, fibre or granules impregnatedwith the desired microbiological agent floats on the surface of water 37in the tank.

[0033] In FIG. 4 a tank 40 again has an inlet 41 in its roof 42 and anoutlet 43 in its floor 44. A vent 46 with a filter 47 is also providedin roof 42. In this embodiment a non-floating layer 45 of foam, granulesor fibre, suitably impregnated with the desired agent lies on the floor44 of the tank.

[0034] It will be appreciated that the embodiment of FIGS. 1 to 4 areall variants of the second general embodiment of the invention and thatin each instance, the water, or other liquid, must pass through themicrobiological agent carrying layer on its journey from the inlet tothe outlet. Good contact is, therefore, ensured for all the water beforeit is drawn off for use.

[0035]FIGS. 5, 6 and 7 represent embodiments within the first generalembodiment of the invention.

[0036] In FIG. 5 a tank 50 is made of a material containing amicrobiological agent or has a coating of such an agent applied to itsinternal surfaces. Water can enter through inlet 51 in roof 52 and leavethrough outlet 53 in floor 54. The roof contains a vent 56 with anoptional air filter 57.

[0037] Inside the tank a paddle 58 attached to an arm 58A is rotatableby external motor 59. Thus when the paddle 58 is submerged in water inthe tank, it can be rotated to agitate the water and to cause improvedcontact between the water and the treated tank surfaces.

[0038] In FIG. 6 a tank 60 is made of similar material to that of tank50. It has an inlet 61 in its roof 62 and an outlet 63 in its floor 64.It also has a vent 66 with a filter 67 in its roof 62. Outlet 63 leadsvia a non-return valve 68 to the desired end use, e.g. a dispensenozzle, not shown, for the water. A recirculation loop 69 runs frombetween outlet 63 and non-return valve 68 to a further inlet 70 in roof62 of the tank. A pump 71 in the recirculation loop enables water intank 60 to be pumped either continuously or intermittently from the tankaround loop 69 and back to the tank, thereby improving contact time withthe internal surfaces of the tank for all the water.

[0039] In FIG. 7 a tank 80 is made of similar material to that of tanks50 and 60. It has an inlet 81 in its roof 82 and an outlet 83 in itsfloor 84. It also has a vent 86 with a filter 87 in its roof 82. As inFIG. 6, outlet 83 leads via a non-return valve 88 to the desired end usefor the water. A recirculation loop 89 leads back into the tank viainlet 90 in the tank roof. Again loop 89 runs from between outlet 83 andnon-return valve 88. A pump 91 enables water to be recirculated from thetank and around the loop.

[0040] In this embodiment the recirculation loop also contains a chamberor cartridge 92 filled with a microbiological agent, e.g. in foam orgranule carrier form 93. Thus the recirculation not only improvescontact with the tank walls but provides a further microbiologicalcontact zone in the cartridge 92.

[0041] The cartridge 92 and/or an insert carrying the microbiologicalagent within the cartridge 92 may be replaceable after a period of use.In this way, the microbiological agent may be renewed to maintain theeffectiveness of the agent to kill or deter microbiological growth inthe water. In a variation of the FIG. 7 arrangement, the microbiologicalagent may be present in the re-circulation loop only, e.g. in cartridge92.

[0042] The cartridge 92 and/or insert may be replaced at regularintervals of time. Alternatively, the cartridge 92 and/or insert may bereplaced after a pre-determined volume of water has been drawn off. Inthis way, variations in use of the apparatus are taken into accountbefore replacing the cartridge 92 and/or insert.

[0043] Means may be provided to give a visual and/or audible warninglocally or at a remote location when the cartridge 92 and/or insertneeds to be replaced. For example a light or buzzer may be activated onthe apparatus or a signal may be transmitted to a remote location whenthe cartridge 92 and/or insert needs to be replaced.

[0044] It will be understood the invention is not limited to theembodiments above-described.

[0045] For example, features in any of the embodiments may be employedseparately or in combination with features from any of the otherembodiments to provide apparatus with a microbiological agent to kill ordeter microbiological growth.

[0046] Thus, the re-circulation arrangements shown in FIGS. 6 and 7 mayequally be used in conjunction with any of the tank arrangements of theother Figures.

[0047] Where the microbiological agent is provided by a carrier or othersupport medium arranged internally or externally of the tank, it ispreferably renewable to maintain the effectiveness of the agent. Inother words, the carrier or support medium is replaceable.

[0048] The apparatus may include means to monitor the quality of thewater in the reservoir and/or re-circulation loop where provided. Themonitoring means may provide a warning of microbiological growth outsideacceptable limits. The monitoring means may provide a warning locally orgenerate a signal for transmission to a remote location. The monitoringmeans may activate a shut-off valve to prevent dispense of water if thedetected quality is outside acceptable limits.

[0049] The invented apparatus may be used to provide a source of waterin a beverage dispenser for hot and/or cold drinks. The water may bemixed with other components e.g. flavouring agents, colouring agents,sweeteners etc, to produce different beverages for user selection. Thedispenser may include a carbonator for dispense of still or carbonatedwater with or without additional components added.

[0050] Other modifications and improvements will be apparent to thoseskilled in the art and are deemed within the scope of the invention.

1. A liquid storage apparatus, the apparatus comprising a reservoir forthe liquid, the reservoir containing a microbiological agent to kill ordeter microbiological growth, the microbiological agent being in aphysical form to present a sufficient contact area with the liquid toprovide the required effect.
 2. An apparatus according to claim 1, inwhich the walls of the reservoir are formed of material in which themicrobiological agent is present or onto which it is coated and anagitator is provided in the reservoir to promote increased contactbetween the walls and the liquid.
 3. An apparatus according to claim 1,in which the walls of the reservoir are formed of material in which themicrobiological agent is present or onto which it is coated and theapparatus includes a recirculation loop to pass the liquid out of andback into the reservoir.
 4. An apparatus according to claim 3, in whichthe recirculation loop includes a treatment station containing furthermicrobiological agent.
 5. An apparatus according to claim 4, in whichthe station includes a labyrinth to further improve contact time withthe agent.
 6. An apparatus according to claim 1, in which themicrobiological agent is present in the reservoir in or on a carrier,which carrier is in open-cell foam, fibre or granular form to provide asurface area for contact with the liquid.
 7. An apparatus according toclaim 6, in which the microbiological agent is incorporated in aplastics composition which has been processed to the carrier form.
 8. Anapparatus according to claim 6 or 7, in which the carrier is of volumeto completely fill the reservoir and the reservoir is vented.
 9. Anapparatus according to claim 6 or 7, in which the reservoir is unventedand contains a collapsible membrane as a barrier to atmosphere.
 10. Anapparatus according to claim 6 or 7, in which the carrier forms a layerthrough which the liquid must pass on its travel from the inlet to theoutlet of the reservoir.
 11. An apparatus according to claim 10, inwhich the layer is attached to the walls of the reservoir.
 12. Anapparatus according to claim 10, in which the layer floats on the liquidthat has passed through it.
 13. An apparatus according to claim 6 or 7,in which the reservoir has a sump in its floor and the carrier is in thesump.
 14. An apparatus according to any one of claims 6 to 13, in whichthe carrier is a foam material used in a compressed state.
 15. Anapparatus according to any one of claims 6 to 14, which includes arecirculation loop to pass the liquid out of and back into thereservoir.
 16. An apparatus according to claim 15, in which therecirculation loop includes a treatment station containing furthermicrobiological agent.
 17. A liquid storage apparatus, the apparatuscomprising a reservoir for the liquid and a recirculation loop to passthe liquid out of and back into the reservoir, the recirculation loopincluding a treatment station containing a microbiological agent to killor deter microbiological growth.
 18. An apparatus according to any oneof the preceding claims, in which the microbiological agent isrenewable.
 19. An apparatus according to claim 18, in which themicrobiological agent is provided by a replaceable support medium. 20.An apparatus according to claim 18 or claim 19, in which means isprovided for indicating when the microbiological agent needs to berenewed.
 21. An apparatus according to any one of the preceding claims,in which means is provided for monitoring water quality and providing awarning if the water quality is outside acceptable limits.
 22. A methodof killing or deterring microbiological growth in a liquid contained ina reservoir by providing a microbiological agent in a physical form forcontact with the liquid and promoting contact between the liquid and theagent.
 23. A beverage dispenser including liquid storage apparatusaccording to any one of the preceding claims.